Local-Global F E Analysis of Column-Supported Cooling Towers

In this paper, the local-global strategy is extend to column-supported reinforced concrete shell structures and applied to the nonlinear structural analysis of a column- supported reinforced concrete cooling tower shell with imperfections. To solve this problem, a general shell element and a transitional shell element as well as a column element derived earlier have been extended considering the nonlinear behavior of the concrete. First, a perfect reinforced concrete cooling tower supported by columns is selected as the base line numerical model. The stress distribution around the intersection with the columns is analyzed under an axisymmetric loading by the local global strategy and is verified by comparing with a previous analysis. Second, a column-supported R/C cooling tower with an imperfection is considered and the nonlinear behavior is computed under a combination of dead load and static wind pressure. The local-global analysis produces similar results with those obtained by the general finite element analysis and brings considerable reduction of computing effort, so that this method is applicable to verify the safety the local behavior of the cooling tower within the limitation of present design requirements.